1. Determining Sex Sex Chromosomes determine sex Males have an X and a Y
Females have 2 Xs
X and Y & X and X are homologous pairs
If a sperm with an X fertilizes the egg the offspring is female
If a sperm with a Y fertilizes the egg, the offspring is male
Males determine gender

2. Karyotyping
Karyotype- morphology and number of entire set of chromosomes of a species
Chromosomes are arranged and numbered in size from largest to smallest
Can help discover genetic disorders

3. Karyotype

4. How are they made? Cell is stopped in metaphase of mitosis
Chromosomes are stained
Chromosomes are arranged

5. How to match chromosomes
3 ways
1.) Size- lower numbers are largest
Y chromosome is smallest
X chromosome is last – about same size as 8 or 9
2.) Banding pattern- homologous pairs have same banding
3.) Position of centromere- not always in the center

6. Your Job
You are highly respected doctors specializing in genetic disorders. Families pay you large sums of money to determine if their children have any genetic disorders. Recently a family has asked you to help them. Create a karyotype of their child’s chromosomes and determine if they have a genetic disorder. If they do, research it so that you can explain it to the family. Remember, they are counting on you!